One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water?video.That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.

One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water?video.That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.

Studies such as a recent Harvard School of Public Health investigation found that the consumption of whole fruits is associated with a significantly lower risk of type 2 diabetes, whereas fruit juice consumption is associated with a higher risk, highlighting the dramatic difference between eating whole fruits and drinking fruit juice. Cholesterol serves as another example. If we eat apples, our cholesterol drops. On the other hand, if we drink apple juice, our cholesterol may actually go up a little. Leaving just a little of the fiber behind--as in cloudy apple juice--was found to add back in some of the benefit.

We used to think of fiber as just a bulking agent that helps with bowel regularity. We now know fiber is digestible by our gut bacteria, which make short chain fatty acids (SCFAs) out of it. SCFAs have a number of health promoting effects, such as inhibiting the growth of bad bacteria and increasing mineral absorption. For example, experimentally infused into the rectum of the human body, SCFAs can stimulate calcium absorption, so much so that we can improve the bone mineral density of teenagers just by giving them the fiber naturally found in foods like onions, asparagus, and bananas.

Our good bacteria also uses fiber to maintain normal bowel structure and function, preventing or alleviating diarrhea, stimulating colonic blood flow up to five-fold, and increasing fluid and electrolyte uptake. The major fuel for the cells that line our colon is butyrate, which our good bacteria make from fiber. We feed them, and they feed us right back.

If the only difference between fruit and fruit juice is fiber, why can't the juice industry just add some fiber back to the juice? The reason is because we remove a lot more than fiber when we juice fruits and vegetables. We also lose all the nutrients that are bound to the fiber.

In the 1980's, a study (highlighted in my video, Juicing Removes More Than Just Fiber) found a discrepancy in the amount of fiber in carob using two different methods. A gap of 21.5 percent was identified not as fiber but as nonextractable polyphenols, a class of phytonutrients thought to have an array of health-promoting effects. Some of the effects associated with the intake of dietary fiber in plants may actually be due to the presence of these polyphenols.

Nonextractable polyphenols, usually ignored, are the major part of dietary polyphenols. Most polyphenol phytonutrients in plants are stuck to the fiber. These so-called missing polyphenols make it down to our colon, are liberated by our friendly flora and can then get absorbed into our system. The phytonutrients in fruit and vegetable juice may just be the tip of the iceberg.

For those that like drinking their fruits and vegetables, these findings suggest that smoothies may be preferable. I can imagine people who eat really healthy thinking they get so much fiber from their regular diet that they need not concern themselves with the loss from juicing. But we may be losing more than we think.

For those that like drinking their fruits and vegetables, this suggests smoothies are preferable. I can imagine people who eat really healthy thinking they get so much fiber from their regular diet that they need not concern themselves with the loss from juicing, but they may be losing more than they think.

Glaucoma is the second leading cause of legal blindness in white women, and the number one cause of blindness in African-American women. In a study I profile in the video Greens vs. Glaucoma, researchers chose a population of African-American women to study the effects of fruit and vegetable consumption on glaucoma risk because they were specifically interested in studying the effect of foods with the highest concentration of those eye-protecting phytonutrients like zeaxanthin. Zeaxanthin is found primarily in plants such as kale and collard greens. (It is also found in eggs--find out how much in Egg Industry Blind Spot). However, we'd be lucky if we could find one in ten white people eating even a single serving of these dark green leafy vegetables a month, whereas nearly nine out of ten African-American women in the study consumed this amount.

What did the researchers find? Well, as I've stressed over the years, all fruits and vegetables are not the same (see for example, How to Reach the Antioxidant "RDA"). Whether the participants hardly ever ate bananas or had one or more every day didn't seem to matter much in terms of the risk of glaucoma. However, eating only a couple oranges every week was associated with dramatically lower risk. Orange juice was not associated with a lower risk, though, even if drunk every day. A similar finding was found for peaches: fresh peaches seemed to help, but canned peaches didn't.

Similarly the intake of vegetables in general as a catch-all term didn't seem to matter. For example, whether subjects ate a green salad twice a week, once a week, or zero times a week didn't seem to matter when it came to reducing glaucoma risk, but most people's salads are pretty pitiful. It was a different story for kale and collard greens: just two or three servings a month was associated with half the risk of glaucoma compared to once a month or less.

It may be especially important for white people to consume kale and collard greens. The lighter our eye color, the more greens we need to eat. Blue eyes let 100 times more light through, so people with blue or gray eyes appear significantly more vulnerable to damage compared to brown or black. Green and hazel fall somewhere in the middle.

This is interesting: carrotsappeared to be less protective in black women compared to white women. They suggest it could be a difference in food preparation methods. Perhaps the African-American subjects tended to eat carrots raw, limiting the absorption of certain nutrients, while they chopped and prepared their collard greens with oil, making the nutrients more bioavailable because the absorption of carotenoid phytonutrients depends on the presence of fat. This is why I encourage people to eat nuts or seeds with the greens--such as a little tahini sauce or something.

Why not just take a zeaxanthin pill? We don't know what exactly it is in these wonderful foods that's working their wonders, so it's probably better to just eat our greens rather than supplements. In fact, people that take calcium or iron supplements may even be doubling, quadrupling, or septupling their odds of glaucoma. It's better to get most of our nutrients from produce, not pills.

After we eat, our bodies create free radicals in the process of breaking down our food. That's why we need to eat antioxidant-rich foods with every meal to counteract this oxidation caused by metabolism. We can't just have berries on our oatmeal in the morning to meet our Minimum Recommended Daily Allowance of Antioxidants and call it a day. Each and every meal should contain high antioxidant foods, which means that each and every meal should contain whole plant foods. Antioxidant rich foods originate from the plant kingdom, due to the thousands of different natural antioxidant compounds naturally created by the plants we eat.

Consuming fruits--which are high in phenolic phytonutrients--increases the antioxidant capacity of the blood. When fruits are consumed along with high fat and refined carbohydrate "pro-oxidant and pro-inflammatory" meals, they may help counterbalance their negative effects. Given the content and availability of fat and sugars in the Western diet, regular consumption of phenolic-rich foods, particularly in conjunction with meals, appears to be a prudent strategy to maintain oxidative balance and health.

And of all fruits, berries may be the best source of phytonutrients. In the video, How to Reach the Antioxidant "RDA", you can see an example of the spike in oxidation caused by a Mediterranean meal of pasta, tomato sauce, olive oil, and fried fish. Obviously, given the spike of oxidation, there were not enough tomatoes. Add a glass of red wine, which contains berry phytonutrients from grapes, and we can bring down, but not blunt completely, the level of oxidation. So the meal needs even more plants.

In a study I profile in the video, researchers gave subjects standard breakfast items, resulting in lots of oxidized cholesterol in their bloodstream one to six hours after the meal. But all it took was a cup of strawberries with that same breakfast to at least keep the meal from contributing to further oxidation. In my Food Antioxidants and Cancer video, you can see a comparison of breakfast with berries versus breakfast without.

If we don't consume high-antioxidant plants with breakfast, by lunch we'll already be in oxidative debt. Let's say we ate a standard American breakfast at 6 a.m. If we didn't eat that cup of strawberries with breakfast, by the time lunch rolls around we'd already be starting out in the hyper-oxidized state, and lunch could just make things worse. Since western eating patterns include eating multiple meals a day, including snacks, one can only speculate on the level of biological unrest.

If we have some berries for breakfast, at least we'd be starting out at baseline for lunch. This acute protection is likely due to the antioxidant effects of the strawberry phytonutrients. What if, by lunch, we could be even better than baseline? How about our meals actually improving our antioxidant status?

If, for example, we eat a big bunch of red grapes with our meal, the antioxidant level of our bloodstream goes up and our bodies are in positive antioxidant balance for a few hours. We get the same result after eating enough blueberries. And imagine if in these ensuing hours before our next meal we were sipping green tea, hibiscus tea or even whole cranberries? (See Pink Juice with Green Foam). We'd have a nice antioxidant surplus all day long.

One group of researchers conclude: "These data provide an interesting perspective for advising individuals on food choice when consuming a moderate- to high-fat meal is unavoidable." (Unavoidable? So what, if we're locked in a fast food joint or something?) They suggest chasing whatever we're forced to eat with some berries. Reminds me of those studies I've talked about suggesting that smokers should eat lots of kale and broccoli to reduce the oxidative damage to their DNA. Of course, they could also just not smoke.

In a single day, the systemic stress of all the fat in our blood and "redox imbalance" (being in a mild pro-oxidant state after meals) may seem trivial. Over time, however, these daily insults can lead to problems such as heart disease, contributing to the hundreds of thousands of deaths a year (See The Power of NO).

So if we have that bowl of berries in the morning to meet our minimum daily antioxidant needs can we just call it a day?. Hint: the title of my follow-up video is: Antioxidant Rich Foods With Every Meal.

We need to get a daily minimum of 8-11,000 antioxidant units a day in our food just to stay out of oxidative debt (see my video on The Reason We Need More Antioxidants). To reach that minimum, all we have to do is eat lots of fruits and vegetables, right? Not exactly. Let's say I ate a whole banana during breakfast (in addition to whatever else). For lunch I eat a typical American salad-- iceberg lettuce, half cup of cucumber slices, and canned peaches for dessert. Supper included a side serving of peas and carrots and half a cup of snap peas along with yet another salad. And, finally, let's say I had a cup of watermelon for dessert. I just ate nine servings of fruits and vegetables and am feeling all good about myself. However, I only made it up to 2700 units, less than a quarter of the way to my minimum daily recommended intake. What am I supposed to do, eat 36 servings a day? (For a cool visual of this, check out my video, How to Reach the Antioxidant "RDA").

What if instead of that banana, I had a single serving of blueberries? And instead of iceberg lettuce for that afternoon salad, I ate four leaves of red leaf lettuce, maybe some kidney beans on top, and a teaspoon of dried oregano as a bonus? For a snack, I had an apple and some dates. It's not even suppertime, only had five servings, yet I've left the minimum recommended daily intake of antioxidants in the dust (topping 28,000 units!). That's why it's not just quantity of fruits and veggies that matters, but also the quality. All fruits and veggies aren't the same. I make this point in different ways in videos like Which Fruit Fights Cancer Better? and Anti-Inflammatory Antioxidants. If possible, we should try to choose the healthiest options out there.

Now that it's midday and I've reached my daily minimum of antioxidants with those five super servings, can I just eat whatever I want for dinner? That's probably not a good idea. The estimated minimum antioxidant need of 8,000-11,000 units does not take into account the added amounts needed if other oxidant stressors--"such as illness, cigarette smoke, meat consumption, air pollution, sleep deprivation"--are present. If we had to deal with these stressors we'd need to consume more fruits and veggies just to stay out of the red.

In my video Antioxidant Level Dynamics, I profiled a study that used an argon laser to measure human antioxidant levels in real time. The study's most important finding was that antioxidant levels can plummet within two hours of a stressful event, but it may take up to three days to get our levels back to normal. The take-home message is that, especially when we're sick, stressed, or tired, we should try to go above and beyond the antioxidant food minimum. Ideally, we need to be constantly soaking our bloodstream with antioxidants, meaning that we should consume high-powered fruits and vegetables--like berries, beans, and green tea or hibiscus--all day long.

Recently, researchers compared the ability of eleven common fruits to suppress cancer cell growth in vitro. Which do you think was most effective--apples, bananas, cranberries, grapefruits, grapes, lemons, oranges, peaches, pears, pineapples, or strawberries?

There are many ways to compare the healthfulness of different foods. For example, if you were interested in antioxidants you might compare vitamin C content. If you compared vitamin C content between our two most popular fruits, apples and bananas, then bananas would appear twice as healthy (10 mg in a banana compared to only 5mg in an apple). But vitamin C is just one of thousands of different phytonutrients in fruits and vegetables. It turns out the vitamin C in apples accounts for less than 1 percent of an apple's total antioxidant activity.

In my 5-min video Which Fruit Fights Cancer Better? I show a graph of the total antioxidant content of a red delicious apple. The amount contributed to the vitamin C is so tiny you can hardly see it. Even though there are only about 5mg of vitamin C in a small apple, it has the antioxidant equivalent of 1500 mg of vitamin C! I've reviewed before how taking that much vitamin C straight in a supplement may actually have a pro-oxidant effect and cause DNA damage (in my video Are Vitamin C Pills Good For You?), but you can get three times that antioxidant power eating an apple, without the adverse effects.

Of course there's more than just vitamin C in bananas too. I was surprised to see a study out of Harvard suggesting that bananas were a significant source of anthocyanins, the red/blue/violet phytonutrients found in berries. Maybe I underestimated bananas? They are, after all, technically berries.

Anthocyanins have been found in blue, purple, orange-red, red-purple, and pink-purple wild bananas, but none in domesticated yellow. In the Harvard researchers' defense, they just took values from the USDA, and it turns out USDA apparently made a mistake. There are no anthocyanins in store-bought bananas, and despite twice the vitamin C, bananas are beat out by apples in terms of overall antioxidant power. But that's just measuring the ability of these fruits to quench an oxidation reaction in a test tube. It would be nice to measure actual biological activity.

In the red delicious apple study, researchers also measured the ability of apple extracts, from both peeled and unpeeled apples, to suppress the growth of human cancer cells growing in a petri dish compared to control. Wouldn't it be great to be able to compare that kind of superpower between different fruits? Well, now we can!

In my video Which Fruit Fights Cancer Better? I show a graph of cancer cell proliferation versus increasing concentrations of the 11 most common fruits eaten in the United States. If you drip water on these cancer cells as a control, nothing happens. They start out powering away at 100 percent growth and they keep powering away at 100 percent growth. And pineapples, pears, and oranges don't do much better.

Peaches start pulling away from the pack. At high peach concentrations, cancer cell proliferation drops about 10 percent, but bananas and grapefruits appear to work four times better, dropping cancer growth rates by about 40 percent. Red grapes, strawberries and apples do even better, cutting cancer cell growth up to half at only half the dose, but the two fruits that won, causing a dramatic drop in cancer proliferation at just tiny doses, were lemons and cranberries. So if you look at the effective dose required to suppress liver cancer cell proliferation, apples are more powerful than bananas, but cranberries win the day. And there was no effective dose listed for orange, pear, and pineapple since they didn't appear to affect the cancer cell growth at all.